NES games not storing high scores

[trigger_death]

Pi Model: Raspberry Pi 3 - Model B
Power Supply: CanaKit 5V 2.5A Raspberry Pi 3 Power Supply / Adapter / Charger
RetroPie Version: 4.1
Built From: Pre made SD image. (Boots on Micro SD, filesystem is on Flash Drive)
USB Devices: Keyboard, Flash Drive with filesystem on it
Controller: Wii Classic Controller

So far I've tried Balloon Fight and Tetris on the NES and neither of them are keeping their highscores after opening the game a second time. Is this just how it works with those games or is this a bug. And if it's the first issue then is there a way to work around this for those specific games?

I should also mention the NES manages to successfully save other games like The Legend of Zelda.

[BuZz]

@trigger_death You could save a snapshot if you want to save the scores. Only console games that had support for saving the scores originally on some flash will support score saving.

[BuZz]

https://en.wikipedia.org/wiki/The_Legend_of_Zelda_(video_game)

More than a year later, North America and Europe received releases on the Nintendo Entertainment System in cartridge format, making the game the first home console title to include an internal battery for saving data.

which is why it works for that as the hardware/flash is emulated by the emulator.

some mame games support hiscore saving via a file which details the part of memory which contains the scores etc so the emulator can dump/reload that part. I don't know if any of the nes emulators have any functionality like this.